Hi All,

I have a 1993 300CE M104 HFM injection that I've owned for over 20years. It has 193,000 miles and generally is in beautiful shape. Off and on for a couple of years now it will randomly drop a cylinder at idle and idle a little rough. It would disappear a soon as you touched the gas. Mo st of the time it was fine and cold and hot starting and driveabuility is great. The CEL is not on. It has the updated harness. Coils, wires and plugs are about 5 years old, and car isn't driven much

Over the last couple of weeks, the dropping of cylinders has gotten worse. The longer it idles at a stop light the worse it gets to the point that it stumbles off idle now. It gets to the point that it feels like it's going to stall but doesn't.
No CEL light. The exhaust smells a little rich and you can hear a "spitting" in the exhaust. I installed a NOS OVP last month and thought it helped, but stumble returned

I built a code reader years ago and have a bunch printouts on the codes but am pretty confused now.

I checked the codes using the built in button and got a 6, 17, 25. I cleared the codes, drove it about 40 miles with the stumble and rechecked the codes.

Now using the built button, I get a #6. Using the code reader, it shows #1 on socket 8 and 14.

the trouble code articles I've printed out aren't consistent or I'm not reading them right.
One shows code #6 as "idle speed control inoperative.
Another shows: #6 as "not used"
Another shows: #6 as "idle speed control faulty

Thanks in advance for your help.